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Four concentric hollow spheres of radii R, 2R, 3R, and 4R are given the charges as shown in figure. Then the conductors 1 and 3, 2 and 4 are connected by conducting wires (both the connections are made at the same time.) , The charge on the inner surface of the third conductor is |
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Answer» `-6Q//5`  Let the charge distribution be as shown in fig From gauss's theorem we know that facing surface s of the CONDUCTOR acquire equal and oppsite CHARGES. So `V_(1)=V_(3)` and `V_(2)=V_(4)` `q_(1)+q_(3)-q_(2)=+4Q`.(i) Now, `q_(2)-q_(1)+q_(4)-q_(3)=-6Q`..(ii) `V_(1)=(1)/(4piepsilon_(0))[(q_(1))/(R)+(q_(2)-q_(1))/(2R)+(q_(3)-q_(2))/(3R)+(q_(4)-q_(3))/(4R)]` `V_(2)=(1)/(4piepsilon_(0)[(q_(1))/(2R)+(q_(2)-q_(1))/(2R)+(q_(3)-q_(2))/(3R)+(q_(4)-q_(3))/(4R)]` `V_(3)=(1)/(4piepsilon_(0))[(q_(1))/(3R)+(q_(2)-q_(1))/(3R)+(q_(3)-q_(2))/(3R)+(q_(4)-q_(3))/(4R)]` `V_(4)=(1)/(4piepsilon_(0))[(q_(1))/(4R)+(q_(2)-q_(1))/(4R)+(q_(3)-q_(2))/(3R)+(q_(4)-q_(3))/(4R)]` from `V_(1)=V_(3),q_(1)=-(q_(2))/(3)` from `V_(2)=V_(4),q_(2)=-(q_(3))/(2)` On solving EQ. (ii) `q_(1)=(2Q)/(5),q_(2)=-(6Q)/(5)` and `q_(3)=(12Q)/(5)` Substituting these values in Eq (ii) we get `q_(4)=-2Q` charge on the INNER surface of the third conductor is `-q_(2)=6Q//5` charge on the fouth conductor is `q_(4)-q_(3)=-2Q-(12Q)/(5)=(-22Q)/(5)` potential of conduction 1, `V_(1)=(-3Q)/(40piepsilon_(0)R)=V_(3)` Potential of conductor 2, `V_(2)=(Q)/(8piepsilon_(0)R)=V_(4)` |
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